Recombinant Macaca fascicularis Low affinity immunoglobulin gamma Fc region receptor III (FCGR3A), partial, Biotinylated (Active)

Function

Receptor for the invariable Fc fragment of immunoglobulin gamma (IgG). Optimally activated upon binding of clustered antigen-IgG complexes displayed on cell surfaces, triggers lysis of antibody-coated cells, a process known as antibody-dependent cellular cytotoxicity (ADCC). Does not bind free monomeric IgG, thus avoiding inappropriate effector cell activation in the absence of antigenic trigger (By similarity). Mediates IgG effector functions on natural killer (NK) cells. Binds antigen-IgG complexes generated upon infection and triggers NK cell-dependent cytokine production and degranulation to limit viral load and propagation. Involved in the generation of memory-like adaptive NK cells capable to produce high amounts of IFNG and to efficiently eliminate virus-infected cells via ADCC. Regulates NK cell survival and proliferation, in particular by preventing NK cell progenitor apoptosis (By similarity). Fc-binding subunit that associates with CD247 and/or FCER1G adapters to form functional signaling complexes. Following the engagement of antigen-IgG complexes, triggers phosphorylation of immunoreceptor tyrosine-based activation motif (ITAM)-containing adapters with subsequent activation of phosphatidylinositol 3-kinase signaling and sustained elevation of intracellular calcium that ultimately drive NK cell activation. The ITAM-dependent signaling coupled to receptor phosphorylation by PKC mediates robust intracellular calcium flux that leads to production of pro-inflammatory cytokines, whereas in the absence of receptor phosphorylation it mainly activates phosphatidylinositol 3-kinase signaling leading to cell degranulation (By similarity). Costimulates NK cells and trigger lysis of target cells independently of IgG binding (By similarity). Mediates the antitumor activities of therapeutic antibodies. Upon ligation on monocytes triggers TNFA-dependent ADCC of IgG-coated tumor cells (By similarity). Mediates enhanced ADCC in response to afucosylated IgGs (By similarity)

Subcellular Location

Cell membrane (Single-pass type I membrane protein); Secreted

Tissue Specificity

Lymphocytes and monocytes

Subunit

Forms a heterooligomeric complex with ITAM-containing signaling subunits, either a homodimer of CD247, a homodimer of FCER1G or a heterodimer of CD247 and FCER1G. Interacts (via transmembrane domain) with signaling subunits; this interaction is a prerequisite for receptor complex expression on the cell surface and intracellular signal transduction. Binds the Fc region of antigen-complexed IgG with a preference for IgG1 and IgG3 isotypes (By similarity). Interacts with CD2; this interaction is involved in NK cell activation and cytotoxicity (By similarity). Interacts with S100A4; this interaction inhibits PKC-dependent phosphorylation of FCGR3A (By similarity)

• Rogers K.A. et al. IgG Fc receptor III homologues in nonhuman primate species: genetic characterization and ligand interactions. — J. Immunol. (2006)
• Namenuk A.K. et al. Binding of human IgG to cynomolgus FcR. (FEB-)
• Conrad D. et al. Nomenclature of Fc receptors. IUIS/WHO Subcommittee on Nomenclature of Fc receptors. — Bull. World Health Organ. (1994)